Metabolic acidosis symptoms, complications and treatment

What is metabolic acidosis?

Metabolic acidosis is a buildup of acid in your body. Your kidneys help balance these acids. You can have too much acid because your kidneys are not removing enough of it or because your body is making too much. Metabolic acidosis is common in people with kidney disease because their kidneys are not filtering their blood well enough and can cause a buildup of certain electrolytes. It can also happen in people with diabetes or kidney failure, also called end-stage renal disease (ESRD) or end-stage kidney disease (ESKD).

What are the symptoms of metabolic acidosis?

Many people do not notice symptoms right away. In mild or early cases, you may not feel different at all. As the condition progresses, symptoms can become more noticeable and may include:

• Confusion
• Fast heartbeat
• Nausea
• Headache
• Long and deep breaths
• Loss of appetite
• Vomiting
• Feeling tired
• Feeling weak

When to see a doctor

If you notice a combination of these symptoms, call your doctor. Metabolic acidosis can get worse quickly if left untreated, especially if you have chronic kidney disease (CKD) or diabetes. Early detection and treatment can help protect your kidneys and reduce other health complications.

What are the causes?

Kidney-related causes

• Chronic kidney disease (CKD): As kidney function declines, your kidneys may not remove enough acid from your blood. Studies suggest that up to 2 out of 5 people with CKD have some form of metabolic acidosis, especially as their estimated glomerular filtration rate (eGFR) falls below 30.
• Kidney failure: When your kidneys are severely damaged, they cannot filter waste or balance acid levels effectively. This leads to a more severe form of metabolic acidosis, which may require dialysis. 

Other common causes

• Type 2 diabetes: Diabetic kidney disease is a leading cause of metabolic acidosis. High blood sugar and poor kidney filtration can increase acid in the blood.
• Sepsis or critical illness: Infections or serious illnesses can overwhelm your body and cause acid to build up quickly.
• Certain medicines: Some medicines, like aspirin and certain chemotherapy drugs, can increase acid levels in the body. Always talk to your doctor before starting or stopping any medicine.
• Toxins: Substances like methanol and ethylene glycol (found in antifreeze) can be toxic to the kidneys and may lead to metabolic acidosis if ingested.
• Severe dehydration: Losing a lot of fluid due to illness, diarrhea or vomiting can throw off your body's acid balance.
• Inherited or rare conditions: Certain rare genetic disorders can affect how your kidneys handle acid and bicarbonate, such as lupus and cystinosis.

How is it diagnosed?

Doctors typically use three main tests to diagnose metabolic acidosis, which include a serum bicarbonate test, a blood PH test, and an anion gap calculation. Your doctor may also test your urine for signs of kidney damage.

Blood tests:

Bicarbonate
 
Bicarbonate is a chemical in your blood that helps neutralize acid. Think of it as your body's natural antacid, whichacts as a buffer of waste products. It is measured using a serum bicarbonate blood test, which helps show if your acid levels are too high.

• A normal bicarbonate level is between 22 and 29 mEq/L.
• If your level drops below 22 mEq/L, it may mean your body is too acidic.
• Mild to moderate metabolic acidosis is usually in the 12–22 mEq/L range.
• Levels below 12 mEq/L may indicate severe metabolic acidosis, which requires urgent treatment.

Blood pH

Blood pH is a measure of how acidic or basic your blood is.

• A normal blood pH is around 7.35 to 7.45.
• If your pH falls below 7.35, your blood is too acidic.
• A very low pH (below 7.2) is dangerous and often treated in a hospital.

Anion gap

The anion gap helps doctors figure out what's causing your acidosis.

• It looks at the balance between positively and negatively charged particles in your blood.
• A high anion gap might suggest that your body is making too much acid (such as in diabetes or sepsis).
• A normal anion gap with low bicarbonate might mean your kidneys can't get rid of enough acid.  

Urine
Urine albumin-to-creatinine ratio (uACR): Measures the amount of albumin (a type of protein) compared to creatinine in a urine sample.

Doctors may also use imaging tests, like an ultrasound, which can also be helpful if your doctor suspects a structural problem with your kidneys.

What problems can happen from metabolic acidosis?

Here are some health problems that can happen if metabolic acidosis is not treated:

• Your kidney disease can get worse
• Bone loss (osteoporosis) can lead to a higher chance of fractures in important bones like your hips or backbone
• Muscle loss because of less protein in your body
• Endocrine disorders, which mean that glands that produce hormones in your body are not working like they should
• Slowed growth in children
• Inflammation (swelling, redness, and pain)
• Amyloid accumulation is a build-up of protein in your body that can hurt your joints, organs and brain
• Increased chance of death

How is metabolic acidosis treated?

While there are no FDA-approved therapies for long-term treatment, some medications and lifestyle changes can help manage acid levels.

Your treatment plan will be tailored to your specific needs, so it's important to discuss options with your healthcare provider.

Foods to limit:

• Animal proteins (red meat, poultry, dairy): These can increase acid production.
• Processed foods (fast food, packaged snacks): Often high in salt and acid-forming ingredients.
• Alcohol: Avoid or limit to no more than 1 drink per day for women and no more than 2 drinks per day for men, as it can worsen metabolic acidosis.

Other helpful tips:

• Manage blood sugar: High glucose levels can increase acid buildup.
• Avoid skipping meals: Eating regularly helps prevent ketoacidosis (a type of acidosis).
• Staying well-hydrated helps your kidneys flush out extra acid from your body, which can support better overall kidney function.

Always talk with your doctor or a registered dietitian before making any changes to your diet. A dietitian can help you create a personalized eating plan based on your stage of kidney disease and overall health.  

Visit Kidney Kitchen for recipes, videos, and tips to help you make kidney-friendly meals that support your overall health and nutrition goals.

Medicine

Your doctor may also prescribe medicine to raise your blood's base level and lower the acidity, such as:

• Sodium bicarbonate tablets or powder (such as baking soda)
  • This type of treatment raises bicarbonate levels, which helps protect your bones, muscles and kidneys from damage caused by too much acid.
• Sodium citrate solution or liquid
• Potassium citrate tablets, powder or liquid

It's important to note that potassium-based options are generally avoided in people with CKD unless they have low potassium levels. These medicines work to cancel out the acidity levels. Follow your healthcare provider's directions on how much fluid to drink with these medicines. Always work with your healthcare team to choose the safest and most effective plan.

Sodium bicarbonate

How it helps:

• Raises bicarbonate levels to neutralize acid
• Most common and effective treatment

It may not be ideal if you have:

• High blood pressure
• Heart disease or heart failure
• Edema (swelling)
• Late-stage CKD

Possible side effects:

• Bloating and gas
• Nausea or stomach pain
• Increased fluid retention (due to sodium content)

Calcium-based alternatives

Most people with later-stage CKD have health problems that require them to limit sodium. Sometimes, using sodium-based supplements can make health problems worse. They may have to take a different type of medicine to help instead. These alternatives can help balance acid levels without adding extra sodium.

For those who need to limit sodium, doctors may recommend:

• Calcium citrate
• Calcium carbonate
• Calcium acetate

Potential risks:

• May raise blood calcium levels
• Long-term use could increase kidney stone risk

Always consult your healthcare team first. They'll evaluate your kidney function, other health conditions, and current medications to determine the safest option for you. You'll need regular blood tests to monitor your bicarbonate levels and watch for side effects. Report any new symptoms like increased swelling, persistent nausea, or changes in urination, as these may signal a need to adjust your treatment.

What to do next

If you're living with kidney disease or at risk for metabolic acidosis, talk to your doctor about getting tested. The earlier you understand your acid levels, the more options you have to protect your health. Regular checkups, personalized care, and small lifestyle changes can help you feel your best and slow down kidney damage. Ask your healthcare provider about how often you need to have your labs checked and if you have any symptoms that indicate you need further treatment.